(734e) High Pressure Adsorption Behaviors of CO2/CH4 Mixture On Korean Coal

High pressure adsorption behaviors of CO₂/CH₄
mixture on Korean coal

Hae Jung Kim, Hyeon
Hui Lee and Chang-Ha Lee^*

Department
of Chemical and Biomolecular Engineering, Yonsei University, Seoul, Korea

^*E-mail: leech@yonsei.ac.kr, Tel: +82-2-2123-2762

CO₂ storage in geological formations has
been regarded as one of the promising methods to reduce anthropogenic CO₂
emissions. Among geological sequestration sites, un-mineable coal seams offer
attractive sites because it can have a chance for the recovery of CH₄
from a coal seam (ECBM) in addition to CO₂ sequestration. Due to the
higher adsorption affinity of CO₂ to coal, the injected CO₂
displaces the pre-adsorbed CH₄ being stored in the coal seams.

To evaluate preferential CO₂ adsorption
on coals, adsorption and desorption behaviors of pure CO₂ and CH₄
on Kyungdong coal (anthracite coal, South Korea) were measured and competitive
adsorption experiments with CO₂/CH₄ mixture gas were
performed in this study. Adsorption behavior of anthracite with a significant
amount of mineral matter was measured at 318 and 338 K up to 150 atm. To
evaluate the moisture effect, a set of experiments on dry and wet coal was
carried out by a volumetric method.

The water dissolved in the CO₂-rich (or
CH₄-rich) gas phase as well as coal swelling should be considered in
evaluating the sorption capacity of a wet coal seam. In the mixture, the mole
ratio of CO₂ to CH₄ was lower in the equilibrium phase
than in the source gas at both temperatures throughout all pressures. It
indicated the preferential CO₂ adsorption in competitive adsorption
condition, and it could also be confirmed from higher CO₂ adsorbed
amounts than CH₄ from the mixture. When the adsorption isotherms of
mixture gas were compared with pure gas, those showed similar behaviors with
pure CO₂ rather than CH₄.

References

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[3] H.J. Kim, Y. Shi, J. He, H.-H. Lee, C.-H. Lee, Chem. Eng. J. (2011),
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